Move experimental Back-BDB2 to Attic

configure

configure.in

include/portable.h.in

include/portable.nt

servers/slapd/back-bdb2/Makefile.in

servers/slapd/back-bdb2/abandon.c

servers/slapd/back-bdb2/add.c

servers/slapd/back-bdb2/alias.c

servers/slapd/back-bdb2/attr.c

servers/slapd/back-bdb2/back-bdb2.h

servers/slapd/back-bdb2/backbdb2.dsp

servers/slapd/back-bdb2/backbdb2.dsw

servers/slapd/back-bdb2/bind.c

servers/slapd/back-bdb2/cache.c

servers/slapd/back-bdb2/close.c

servers/slapd/back-bdb2/compare.c

servers/slapd/back-bdb2/config.c

servers/slapd/back-bdb2/dbcache.c

servers/slapd/back-bdb2/delete.c

servers/slapd/back-bdb2/dn2id.c